Date: Fri, 11 Nov 2016 17:27:36 +0100
From: Joerg Roedel <joro@8bytes.org>
To: Robin Murphy <robin.murphy@arm.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        iommu@lists.linux-foundation.org, Will Deacon <will.deacon@arm.com>,
        Hanjun Guo <hanjun.guo@linaro.org>,
        Marc Zyngier <marc.zyngier@arm.com>,
        "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        Tomasz Nowicki <tn@semihalf.com>, Jon Masters <jcm@redhat.com>,
        Eric Auger <eric.auger@redhat.com>, Sinan Kaya <okaya@codeaurora.org>,
        Nate Watterson <nwatters@codeaurora.org>,
        Prem Mallappa <prem.mallappa@broadcom.com>,
        Dennis Chen <dennis.chen@arm.com>, linux-acpi@vger.kernel.org,
        linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v7 04/16] drivers: iommu: make of_iommu_set/get_ops() DT
 agnostic
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On Fri, Nov 11, 2016 at 04:17:37PM +0000, Robin Murphy wrote:
> In the original of_iommu_configure design, the thought was that an ops
> structure could be IOMMU-instance-specific (hence the later-removed
> "priv" member), so I suppose right now it is mostly a hangover from
> that. However, it's also what we initialise a device's fwspec with, so
> becomes important again if we're ever going to get past the limitations
> of buses-which-are-not-actually-buses[1].

Yeah, I discussed this with a few others at LPC. My current idea is to
tell the iommu-core which hardware-iommus exist in the system and a
seperate iommu_ops ptr for each of them. Then every struct device can
link to the iommu-instance it is translated by.

We are not there yet, but this will give you the same per-device
iommu-ops as implemented here.


	Joerg